In order to pass acceptable amounts of heat across a thermal interface, tremendous amounts of pressure must be applied. This creates large action and reaction forces and drives the structural overhead weight up considerably. To distribute the load evenly, prior art devices had complex mechanisms with complex load paths. And in a blind mate application, the reaction forces will drive the structural weight up and, correspondingly, the required latch strength up. In order for the thermal interface to function efficiently, prior art devices tended to have large areas of contact on the thermal interface. These areas of contact were also required to be very smooth. Prior art devices also had no acceptable way to get the heat to or away from the thermal interface. In effect, the devices were large and heavy, and they did not successfully compete, with respect to weight and volume, with a fluid coupling.
In fluid couplings, a disadvantage is the spillage of fluid when the coupling is mated and de-mated, and the couplings can leak and/or cause contamination. Prior art fluid couplings have elaborate valve schemes to ensure that fluid does not spill or leak on operation of the coupling. Prior art fluid couplings also have elaborate seals or o-rings to help prevent leakage, and tight alignment tolerances on mating. In the prior art, it was very difficult to design items with tight alignments over the distance required to mate the fluid coupling. Many of the prior art fluid couplings require a constant force to maintain coupling mating or to mate the coupling. This force drives the mounting structural weight up to react to the mating force. For safety, some prior art fluid couplings also required sensors and ports to verify operation before allowing fluid to pass.
Other methods for thermal control, such a fluid regulators or electrical heaters, were complex and heavy or required electrical power, a control system, and sensors.